Plan your visit to Display Week 2012 with an advance look at some of the most exciting developments to be revealed in this year's technology sessions.
by Jenny Donelan
THE Society for Information Display's annual Symposium is the core of Display Week. The hundreds of papers presented each year represent the best of the most recent research and development in numerous areas of display technology. This year's Symposium, to be held in Boston, Massachusetts, June 5-8, will offer an enormous range of technical display-related presentations impossible to find at any other venue.
As in previous years, sessions are organized by subcommittees, whose members have chosen the most cutting-edge and informative papers in their chosen areas. Those areas include active-matrix devices, applications, applied vision, display electronics, display manufacturing, display measurement, display systems, emissive displays, flexible displays, liquid-crystal technology, OLEDs, projection, and touch and interactivity.
In addition to the above, SID has designated special topics of interest that are especially timely and important to our industry: 3-D, Green Technologies, Solid-State Lighting, and Flexible Electronics and Printed Displays. Attendees at Display Week 2012 will have the opportunity to gain comprehensive knowledge of each of these special topics not only by way of the presentations during the four-day technical symposium, but through the special Sunday Short Courses and Monday Seminars, and with a business perspective from the Business and Investors Conferences and the Market Focus Conferences.
The following session highlights are but a small portion of what awaits attendees at Display Week 2012. Come join us to find out what's happened in our industry over the past year, and what's going to happen next. See you in Boston!
Active-Matrix Devices: TFT Oxide Prepares to Go Mainstream
Two distinct themes emerged among this year's crop of active-matrix papers, according to sub-committee chair Russel Martin. The first involves the tremendous amount of work cur-rently going into oxide semiconductors, which, as viable alternatives to amorphous-silicon TFTs, are moving from concept to manufacturing. The second is represented by very-high-resolution TV panels, including an 8K x 4K AMLCD. "These are just amazing leaps in high-end OLEDs and AMLCDs – the growth never stops," says Martin.
Among the oxide-TFT papers to watch for are "Implementation of 240-Hz 55-in. Ultra-Definition LCD Driven by a-IGZO semiconductor TFT with Copper Signal Lines" by Namyong Gong of LG Display and "Research, Development, and Application of Crystalline Oxide Semiconductor" by Jun Koyama of Semiconductor Energy Laboratory Co., Ltd. One of the most exciting papers will be "Development of Super Hi-Vision 8K x 4K Direct-View LCD for Next-Generation TV" by Takeshi Kumakura of Sharp Corp., a look at an 85-in. concept panel that is the world's first direct-view display for 8K x 4K resolution.
Applications: From Augmented Reality to Homeland Security
Applications represent that exciting stage of display development when theories and concepts become actual products. This year's applications papers range from stereoscopic and autostereoscopic displays to solid-state lighting to novel and emerging displays. One of the more interesting in the latter category is "Detection of Ionizing Radiation by Plasma-Panel Sensors: Cosmic Muons, Ion Beams, and Cancer Therapy," by Peter S. Friedman of Integrated Sensors LLC. Friedman's paper describes the plasma-panel sensor, a new radiation-detector technology based on plasma-display panels, which is being developed for a number of scientific and commercial applications, including homeland security, cancer treatments, and medical imaging. Also of interest is the paper "Sensing and Augmented-Reality Technologies for Mobile 3-D Platforms" by Chan Yuan of Sharp Laboratories of America, which describes algorithms that can enable novel user experiences by providing depth sensing for mobile devices. Possible 3-D and augmented-reality applications include gaming, tactical and situational awareness, scientific visualization, video surveillance, and robotics. The invited paper "Color-Accurate Monitors" by Adi Abileah of Planar will discuss the specifications for highly accurate color monitors as required by applications such as printing, graphic arts, photography, film-making and editing, medicine, art, and geospatial research. (Note: Abileah is being honored with SID's 2012 Otto Schade Prize for his contributions to display performance.)
Applied Vision: Seeing in 3-D
3-D is by far the biggest trend in applied-vision papers this year. "Almost half the papers are related to 3-D," says subcommittee chair Yi-Pai Huang. Of those, about 75% are related to 3-D perception and 3-D comfort, so there is a session devoted to each of these applied-vision aspects of 3-D.
Of particular note is a poster paper titled "Comparison of Simultaneous Measurement of Lens Accommodation and Convergence in Natural Vision and 3-D Vision" by Tomoki Shiomi of Nagoya University. The author's team set out to study the issue of lens accommodation and convergence, which is thought to be a major source of discomfort for people viewing 3-D imagery. The team invented a method to simultaneously measure accommodation and convergence and used it to measure them in both natural vision and 3-D vision. "This is something that has not been done before," says Huang. Surprisingly, the authors found very little difference between natural vision and 3-D vision in terms of accommodation and convergence, which suggests there could be another reason for viewer fatigue when viewing 3-D images.
Another paper to check out is "3-D Looks More Real and Is Funny: Comparing the Children's and Adults' 3-D-Related Experiences," by Viljakaisa Aaltonen of Nokia Research Center, which looks at users' experience of 3-D images. In the study, 80% of children said they would choose the 3-D format over 2-D, whereas only 26% of adults preferred 3-D. "The children want it but they do not have money to buy it," says Huang, adding that this bodes well for the future – if 3-D content and hardware providers can wait long enough for those kids to grow up and make money.
Display Electronics: LCD Panels Drive Tablet Innovations
Intra-panel interfaces were a popular topic for display-electronics papers this year, according to chair Taesung Kim, who attributes the interest to the rise of tablets, especially ultra-high-resolution varieties that require high-bandwidth interfaces. One session is devoted to intra-panel interfaces and leads off with the paper, "A 1.4-Gbps Intra-Panel Interface for Chip-on-Glass TFT-LCD Applications" by Dongmyung Lee of Samsung Electronics Co., Ltd.. Lee's paper describes a high-speed intra-panel interface with an enhanced reduced voltage differential signaling (eRVDS) scheme implemented in a 0.18-μm high-voltage CMOS process for chip-on-glass TFT-LCD applications. Measured results demonstrate a maximum data rate of 1.4 Gbps from a 1.8-V supply voltage with a WQXGA 60-Hz chip-on-glass TFT-LCD prototype panel.
Display Manufacturing: Oxide TFT and Roll-to-Roll Require New Processes
Much has been happening in display manufacturing this year. According to committee chair Don Carkner, trends for 2012 include new manufacturing options such as simulation and modeling and new processes such as replacing vacuum deposition with 3-D printing. Two other major trends are better performance and lower cost manufacturing for thin-film oxides, as exemplified in the paper "Manufacturing Issues for Oxide-TFT Technologies for Large-Sized AMOLED Displays" by Toshiaki Arai of Sony Corp., and the examination of substrates, including those that are thinner, lower cost, and flexible. Examples of papers in this category include "Flexible Hybrid Substrates of Roll-to-Roll Manufacturing for Flexible-Display Application" by Yung Hui Yeh of ITRI, "A 3-D Cover Glass for Mobile Devices" by Prakash Panda of Corning, and "Role of Glass in Manufacturing: The Next Generation of Advanced Displays" by Peter Bocko of Corning.
Display Measurement: How to Measure What's New
Researchers involved in display measurement face a never-ending challenge: as new display technologies emerge and develop, so must the methodologies used to measure them. Two papers of note this year address issues prompted by relatively new technologies; in the first, Dupont looks at lifetime issues in terms of the demands of future OLED TVs. In the second, E Ink examines measurements for reflective technology.
In the paper, "Influence of TV Media Content on Display Lifetime and Image-Sticking Measurement Techniques" by Andrew Johnson of Dupont Displays," the author states that "both lifetime and image-sticking measurement techniques are well established but are somewhat uncharacteristic of actual TV usage" and proposes modifications that better represent actual usage demands from TV media. "I think this will be interesting and maybe a little controversial," says chair Tom Fiske.
Another paper of interest is "Viewing-Angle Measurements on Reflective e-Paper Displays" by Dirk Hertel of E Ink. Says Fiske, "The measuring of reflective displays is a tricky business because you should take into account the ambient-light geometry – whether it's a cloudy or a sunny day, whether you have lots of small point sources around the room or big luminaries. It's more complicated than pointing a photometer at a regular emissive display. The authors suggest some ways of zeroing in on particular lighting geometries to make measurements."
Display Systems: High-Speed Holographs
Two major trends in display systems are backlighting and 3-D. A 3-D related paper to watch for is "Real-Time Dynamic Holographic Display Based on a Liquid-Crystal Thin Film" by Hongyue Gao of Virginia Tech and Shanghai Jiao Tong University. The author describes a high-speed rewritable holographic technology that uses a liquid-crystal thin film without an applied electric field. The holographic response time is about 1 msec, and video displays have been achieved. Explains chair Brian Schowengerdt, "A high-resolution holograph is projected onto a film and it stays there until it is erased and replaced by the next image in the series. It provides the potential for a digital holographic display capable of full-speed motion video."
In the area of backlighting, the paper, "A High-Efficiency Wide-Color-Gamut Solid-State Backlight System for LCDs Using Quantum-Dot Enhancement Film" by Jason Hartlove of Nanosys outlines the use of narrow line-width red and green emission from quantum-dot enhancement film stimulated by high-efficiency blue LEDs. According to the author, "This drop-in-solution offers high brightness and good color uniformity at a cost far lower than RGB-LED LCDs or OLED systems."
Emissive Displays: Plasma Gains More Protection
Protective layers in plasma are once again a popular emissive displays topic this year, with six papers alone dedicated to the subject, according to Chair Yong-Seog Kim, who notes that these layers have the potential to reduce cost and increase luminous efficacy in PDPs. One such paper is "Development of MgCaO Protective Layer of Plasma Display Panels for Decreased Discharge Voltage" by Takehiro Zukawa of Panasonic Plasma Display Co. Another exciting development is a 300-μm-thick plasma panel, as described in the paper, "Ultra-Thin Shadow-Mask PDP Fabricated by Vacuum In-line Sealing Technology" by Lanlan Yang of Southeast University.
An exciting late-news paper, also devoted to plasma, is "Development of a 145-in.-. Diagonal Super Hi-Vision Plasma-Display Panel" by Keiji Ishii of Japan Broadcasting Corporation (NHK), which describes the creation of prototype full-resolution Super-Hi-Vision (SHV) plasma-display panels (PDPs with 4320 scanning lines and over 33 million pixels).
Flexible Displays: A Range of Technologies Powers Flexible Displays
There were so many new developments in flexible displays this spring that an entire late-news session was added to feature the following three papers: "Oxide TFTs and Color-Filter-Array Technology for Flexible Top-Emission White-OLED Display" by Makoto Noda of Sony, "11.7-in. Flexible AMOLED Display Driven by a-IGZO TFTs on Plastic Substrate" by Hajime Yamaguchi of Toshiba Corp., and "Flexible Color Active-Matrix EP Display Using Low-Distortion OTFT Backplanes" by Paul Cain of Plastic Logic. Also of note is the paper "A 13.3-in. 200-dpi Flexible Electrophoretic Display Driven by OTFTs Manufactured Using High-Resolution Offset Printing" by Ryuto Akiyama of Sony Corp. Akiyama's work describes a very precise printing method used to achieve 5-μm resolution and ±2.2-μm overlay accuracy in organic thin-film transistors.
Liquid-Crystal Technology: Blue Phase Is Here to Stay
As in 2011, blue phase and alignment are the dominant topics for liquid-crystal displays this year. Research into blue-phase technology has continued with even more enthusiasm: last year there were nine blue-phase papers and this year there are 12. Highlighted papers in that category include "A Microsecond-Response Blue-Phase Liquid-Crystal Device by Yuan Chen and "Low-Voltage and Hysteresis-Free Blue-Phase LCD with Vertical Field Switching University of Central Florida" by Hui Chuan Cheng, both from the University of Central Florida. Both papers examine ways to optimize the performance of the promising blue-phase technology. Also of note is "Dual-Mode Reflective Cholesteric Display" by Rafael Zola of Kent State University (the winner of last year's JSID Outstanding Student Paper of the Year award on another topic). Zola's work describes a potential display in which the bistable mode is suitable for displaying static images. The mono-stable mode is suitable to display video-rate dynamic images.
OLEDs: Growing by Leaps and Bounds
OLEDs, which have had their ups and downs in terms of hype vs. reality, have definitely arrived. Overall, the key OLED themes for this year, according to chair Eric Forsythe, are (1) large-format displays, (2) high-resolution OLEDs for smartphones, (3) head-mounted displays, and (4) solid-state lighting. Without question, one of the highlights at Display Week this year will be the paper, "A 55-in. FHD OLED TV Employing New Tandem WOLEDs" by Chang-Wook Han of LG Display. Says Forsythe, "This TV certainly was the buzz at CES, and the paper will look at various technical aspects of achieving an OLED TV of this magnitude." An exciting late-news arrival, also centering on large format, is "Advanced Circular Polarizer by Using Coatable QWP Technology for Large-Sized OLED Display Applications" by Su Hyun Park of LG Display. This paper proposes the use of a circular polarizer to enhance contrast for outdoor applications where ambient luminance is high.
Projection: Pico-Projectors Poised to Become Hot Products
Projection co-chair Alan Sobel makes a bold statement about what's going on commercially in projection technology: "This will be the year of the pico-projectors," he says. "This technology is going to knock peoples' socks off. It's much better, it's more affordable, and this is the year that it's going to go big." In terms of papers at the Symposium, one notable trend, says Sobel, is the availability of green lasers, which have been challenging to manufacture. One such paper is "Watt-Level Compact Green-Laser Module for a Laser Display" by Chang-Qing Xu from McMaster University.
Another paper of note is "Submillisecond-Response Blue-Phase Liquid Crystal for Color-Sequential Projection Displays" by Sihui He from the University of Central Florida, which reports on the first attempt at using emerging blue-phase liquid-crystal (BPLC) technology for color-sequential projection displays. BPLC exhibits submilli-second response time, which is essential for suppressing the color breakup caused by field-sequential color displays. Both transmissive and reflective projectors with in-plane switching and vertical field-switching modes are discussed in the paper.
The projection sessions also enjoyed the addition of six late-news papers, ranging from "Micro-Mirror System-Level Synchronization Notes" by Sharon Hornstein of Maradin Technologies to "A Passive-Matrix Inorganic LED Array as a Projection Source" by Vincent Lee of Columbia University.
Touch Technology: Secrets Revealed
Choosing papers for the touch symposium can be difficult, according to subcommittee member Geoff Walker. "Touch is still very secretive," he explains. Some companies and researchers are reluctant to share their discoveries. Nonetheless, there are some interesting papers in this year's collection, including "An In-cell Capable Capacitive Touch-Screen Controller with 41-dB SNR and Integrated Display Driver IC for 480 x 864 LTPS Displays" by Murat Ozbas of Synaptics. This paper includes three major areas of focus, according to Walker: "What I call hybrid in-cell/on-cell, fast touches, and a high signal-to-noise ratio."
Also of interest is "High-Transmission Optically Matched Conductive Film with Sub-Wavelength Nano-Structures" by Kazuya Hayashibe of Sony Corp., in which the author describes how his team fabricated a very-low-internal-loss anti-reflection nano-structure (ARS) conductive film with over 99% high transmittance and sufficient surface resistance (270 Ω/) that can be manufactured using roll-to-roll high-productivity methods and is suited for high-contrast touch screens.
The paper "Adding Proximity Detection to a Standard Analog-Resistive Touch-Screen" by Chaouki Rouaissia of Semtech Neuchatel Sarl is an example of doing something new (proximity sensing) with something old (analog-resistive), according to Walker. "They have made their resistive controller able to use the top electrode of the touch screen as a proximity sensor without changing anything in the sensor itself," he explains. Possible applications could include a screen on your dashboard that lights up only as you reach your hand toward it.
Special Focus Areas: Green Technologies, Solid-State Lighting, and 3-D
Each year, the Society for Information Display designates special sessions to explore important and timely display topics. This year's sessions are Flexible Electronics and Printed Displays (covered in the February/March 2012 issue), Green Technologies, Solid-State Lighting, and 3-D.
There are 15 papers devoted to Green Technologies this year, with four sessions titled:
• Driving Methods for Low-Power Displays
• Low-Power Displays and Materials
• Green Optics for Display Systems
• Display Manufacturing: Novel Devices and Green Technology
Of particular interest is the paper "Low-Power High-Color-Gamut PenTile RGBCW Hybrid FSC-LCD" by Candice H. Brown Elliott of Nouvoyance, which describes technology with the potential for lower power consumption and higher color gamut than conventional local-dimming RGB-filtered LCD-TV panels. Another paper to note is "A Novel LCD Structure Using Transparent Polymers Free of Birefringence and Scattering Polymers Free of Wavelength Dependency" by Akihiro Tagaya of Keio University, which proposes a new LCD structure using a directional backlight and a scattering film.
Solid-state lighting promises to save energy and provide design flexibility. And it has offered backlighting manufacturers an opportunity to extend their expertise to general illumination applications, and thus expand their business. This year's symposium includes the following sessions:
• Solid-State-Lighting Applications
• Four Solid-State Lighting Technology Sessions
• Lighting Devices
• Fabrication Processes and Solid-State Lighting.
Papers of note include: "From Backlight to Luminaire" by Tim Dekker of Philips Research Laboratories and "Commercialization of World's First All-Phosphorescent OLED Product for Lighting Application" by Takatoshi Tsujimura of Konica-Minolta Technology Center.
One trend in 3-D that has continued from last year is that there are a lot of sessions: 12 in all, including:
• Stereoscopic Display Applications
• Polarization-Based 3-D Displays
• Advances in 3-D Display Characterization
• Autostereoscopic 3-D Displays
• Advanced and 3-D Display Applications
• LC Lenses for 3-D
• Video Processing for 2-D/3-D
• 3-D and Multiview Projection Lens Design for 3-D Displays
• Volumetric, Lightfield, and Holographic Displays
• 3-D Comfort
• 3-D Perception.
One of the recent trends in 3-D noticed recently by chair Brian Schowengerdt is that "there has been a surge in papers addressing the creation and display of "light fields," which is a shift from the focus on stereoscopic display we have seen in the past. The goal is to accurately re-create in a digital display all elements of the light wavefronts that would emanate from real 3-D objects, including accurate focus cues. Holography is one core technology that can potentially create accurate light-fields – but a number of other technologies, such as volumetric displays, also provide good solutions." This year at Display Week, there is an emphasis on the full light-field ecosystem, from content capture and synthesis to display, with much of that work coming out of MIT, notes Schowengerdt. A keynote address by Ramash Raskar of MIT's Media Lab, entitled "Computational Displays: New Optimization for Interactive Lighting-Sensitive 3-D Displays" will discuss light-field encoding and decoding algorithms. Also from MIT, William Freeman will focus on light-field capture in his talk on "Computational Photography," while James Barabas will discuss the end of the pipeline in "Visual Perception and Holographic Displays." A related paper is "Envisioning a Light-Field Ecosystem" by Kurt Akeley of Lytro, who will present an overview of the full light-field process from capture with plenoptic cameras to 3-D displays capable of displaying light-fields.
Another item of interest, says Schowen-gerdt, is that Disney Research is presenting a paper on a volumetric 3-D technology at SID. "I don't think Disney has typically presented with us," says Schowengerdt. That paper is "A 3-D Volumetric Display Using a Rim-Driven Varifocal Beamsplitter and High-Speed DLP Backlit LCD" by Larry Smoot of Disney Research. •